Riley herbert parker



R. H. PARKER.

SCREW THREAD GAGE.

APPLICATION FILD NOV.1. I918.

Patented June 24, 1919.

UNITED STATES PATENT OFFICE.

RILEY HERBERT PARKER,

0F WINTI-IROP, MASSACHUSETTS, ASSIGNOR TO GILLETTE SAFETY RAZOR COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF DELA- WARE.

SCREW-TI-IREAD GAGE.

Specification of Letters Patent.

Patented June 24, 1919.

To all whom it may concern:

Be it known that I, RILEY HERBERT PAR- KER, a citizen of the United States, residing at Winthrop, in the county of Suffolk and State of Massachusetts, have invented cer tain new and useful Improvements in Screw-Thread Gages, of which the following is a specification.

My invention relates to screw thread gages, and resides in the novel characteristics of the gage hereinafter described in connection with the accompanying drawing,

- in which Figure 1 is a rear view of the gage as preferably constructed;

Fig. 2 is an edge view of the same; and

Fig. 3 is a front view of the gage with a portion of the handle omitted.

The gage illustrated in the drawing con sists essentially of a body portion 2 provided with two peep holes 3 and 4E, and two abutments 5 and 6 secured to the body portion 2 and having V-shaped edges in line with the peep holes 3 and 4 respectively, which are separated by a distance suflicient to include a number of threads of the screw to be tested. The body portion 2 is preferably provided with a handle 7, and the abutments 5 and 6 may be conveniently formed on a single plate 8 detachably secured to the body portion by means of a screw 9, each abutment being cut on an angle corresponding exactly with the angle between adjacent threads of an accurately cut screw which is the standard for the gage. The V-shaped edges of the abutments are separated by a distance which is a predetermined multiple of the exact distance between adjacent threads of the standard screw, and the center of each peep hole in the body portion 2 is preferably located in exact alinement with the edge of the corresponding abutment. i

The device above described is used by placing the screw to be tested on the V- shaped abutments 5 and 6 as shown in Figs. 1 and 3 and then viewing the contact between these abutments and the adjacent Copies of this patent may be obtained for five cents each, by addressing the threads by looking through the peep holes from the opposite or front side of the gage. If the thread being tested conforms exactly to the standard, both sides of each of the abutments 5 and 6 will make contact with the corresponding surfaces of the adjacent threads, this condition being illustrated by the screw 10 in Fig. 1. On the contrary, if the thread is not accurately out one or the other of the abutments will be unable to enter completely into the space between adjacent threads and this condition, which is illustrated by the screw 10 in Fig. 3, will be indicated by a visible line of light between one of said abutments and one or the other of the adjacent threads. The function of the peep holes is to localize and define the lines of sight along which the contact between the abutments and the threads of the screw is observed and to cut off the light from the surrounding background, and I have found that this is done so effectively that a very slight departure of the screw thread from the standard according to which the gage is formed is plainly visible. By removing the plate 8 and substituting another having abutments of different shape the gage may be readily adapted for testing different screws.

I claim 1. A screw thread gage comprising a body portion provided with two peep holes, and two abutments carried by the body portion and each located in line with one of the peep holes, said abutments being shaped and spaced to simultaneously fit a screw thread cut to a predetermined standard.

2. A screw thread gage comprising a body portion provided with two peep holes, and a plate detachably secured to the body portion and carrying two abutments each located in line with one of the peep holes, said abutments being shaped and spaced to simultaneously fit a screw thread cut to a predetermined standard.

Signed at Boston, Mass, this 29th day of October, 1918.

RILEY HERBERT PARKER.

"Commissioner of Batents,

Washington, D. G. 

